Ascent and Descent Apparatus for Liquid Material Spray Printer

ABSTRACT

Disclosed is an ascent and descent apparatus for a liquid material spray printer, which may control a distance between a subject to be coated and a spray assembly optimally. The apparatus includes a predetermined number of rotary shafts installed in a vertical direction and having spiral ridges on outer circumferences thereof, the rotary shafts being selectively rotated by a driving motor; and a lifting member installed to the rotary shafts to support a transferring table to which a subject to be coated is mounted, the lifting member having a spiral ridge with a shape conforming to the spiral ridges of the rotary shafts so that the transferring table is lifted when the rotary shafts are rotated.

TECHNICAL FIELD

The present invention relates to an ascent and descent apparatus for aliquid material spray printer, and more particularly to an ascent anddescent apparatus for a liquid material spray printer, which may controla distance between a subject to be coated and a spray assemblyoptimally.

BACKGROUND ART

Generally, a liquid material spray printer is a device for coatingliquid material on a surface of a subject to print a predeterminedimage. As an example of such a liquid material spray printer, there isan ink-jet printer that may coats an ink material for printing.

The liquid material spray printer includes a transferring table on whicha subject to be coated is mounted, a transferring device forreciprocating the transferring table so that liquid material may becoated on the subject, an ascent and descent device forascending/descending the transferring device to a height suitable forliquid material coating, and a spray assembly installed at a substantialcenter of the transferring device to be capable of reciprocating in adirection perpendicular to a moving direction of the transferring table.The spray assembly contains liquid material and is provided with anozzle capable of spraying the liquid material to the subject to becoated. Such a liquid material spray printer is disclosed in KoreanUtility Model Registration Nos. 20-0300099 and 20-0290304.

However, the liquid material spray printer may print an image only on asubject with a regulated size since a distance between the sprayassembly and the transferring table is previously set. That is to say,it is impossible to print images on subjects with various sizes andshapes by using only one liquid material spray printer.

In particular, as interests for product advertisement are recentlyincreased and designs become diversified, there is a need for a liquidmaterial spray printer that is capable of printing various images withvarious colors on surfaces of subjects with various sizes and shapes.

DISCLOSURE OF INVENTION Technical Problem

The present invention is designed to solve the problems of the priorart, and therefore an object of the invention is to provide an ascentand descent apparatus for a liquid material spray printer, which maycontrol a distance between a subject to be coated and a spray assemblyto an optimal coating distance required for printing so that it may beused for subjects with various sizes and shapes.

Technical Solution

In order to accomplish the above object, the present invention providesan ascent and descent apparatus for a liquid material spray printer,which includes a pre-determined number of rotary shafts installed in avertical direction and having spiral ridges on outer circumferencesthereof, the rotary shafts being selectively rotated by a driving motor;and a lifting member installed to the rotary shafts to support atransferring table to which a subject to be coated is mounted, thelifting member having a spiral ridge with a shape conforming to thespiral ridges of the rotary shafts so that the transferring table islifted when the rotary shafts are rotated.

Preferably, the rotary shafts include a shaft gear installed to each ofthe rotary shafts; and a driving force transferring member installed forconnecting the shaft gears with each other so as to transfer a drivingforce, whereby at least two driving rotary shaft are selectively rotatedusing one driving motor at the same time.

More preferably, the ascent and descent apparatus for a liquid materialspray printer further includes a tension pulley installed between therotary shafts to make the driving force transferring member be curved sothat a predetermined tension is provided to the driving forcetransferring member.

In addition, the ascent and descent apparatus for a liquid materialspray printer may further include a sensor for sensing a distancebetween the subject installed to the transferring table and a sprayassembly for spraying liquid material; and a controller for comparingthe distance with an optimal coating distance required for printing andthen selectively operating the driving motor.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of preferredembodiments of the present invention will be more fully described in thefollowing detailed description, taken accompanying drawings. In thedrawings:

FIG. 1 is a perspective view showing a liquid material spray printer towhich an ascent and descent apparatus for a liquid material sprayprinter according to a preferred embodiment of the present invention isinstalled;

FIG. 2 is a plane view showing the liquid material spray printer of FIG.1;

FIG. 3 is a sectional view taken along II-III′ line of FIG. 2;

FIG. 4 is a sectional view taken along IV-IV′ line of FIG. 1;

FIG. 5 is a perspective view showing a gearbox fixing device of theliquid material spray printer of FIG. 1; and

FIG. 6 is an exploded perspective view showing a slider member of FIG.5.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in detail referring to thedrawings. the terms used should not be construed as limited to generaland dictionary meanings but based on the meanings and concepts of theinvention on the basis of the principle that the inventor is allowed todefine terms appropriate for the best explanation. Therefore, thedescription herein the scope of the inventiont be understood that otherand modifications could be made thereto without departing from thespirit and scope of the invention.

In addition, in this specification, in order to describe an ascent anddescent apparatus for a liquid material spray printer according to apreferred embodiment of the present invention, a liquid material sprayprinter to which the ascent and descent apparatus is installed is alsodescribed together.

FIG. 1 is a front view showing a liquid material spray printer to whichan apparatus for fixing a gearbox of the liquid material spray printeraccording to a preferred embodiment of the present invention isinstalled, FIG. 2 is a plane view showing the liquid material sprayprinter of FIG. 1, FIG. 3 is a sectional view taken along III-III′ lineof FIG. 2, and FIG. 4 is a sectional view taken along IV-IV′ line ofFIG. 1.

Referring to FIGS. 1 to 4, the liquid material spray printer 200includes a transferring table 10 to which a subject to be coated ismounted, an ascent and descent apparatus 100 for lifting thetransferring table 10, a gearbox 30 for reciprocating the transferringtable 10, and a spray assembly 80 for coating liquid material.

The transferring table 10 includes a sliding flat table 11 on which asubject to be coated is mounted, and a guide flat plate 16 for guidingsliding movement of the sliding flat plate 11.

The sliding flat plate 11 includes a rack gear 12 installed in a lengthdirection thereof, and protrusions 13 a, 13 b that are detected bysensors 17 a, 17 b, 17 c, 17 d sensing a printing range and areciprocating range respectively.

The rack gear 12 is installed in a length direction on the lower surfaceof the sliding flat table 11 to be engaged with a pinion gear 32, asshown in FIGS. 2 and 3. As described later, the rack gear 12 is closelycontacted with the pinion gear 32 by means of an elastic member 46.

The protrusions 13 a, 13 a include a first protrusion 13 a detected bythe first and second sensors 17 a, 17 b sensing the printing range andthe third sensor 17 c sensing an end position of the reciprocatingrange, and a second protrusion 13 b detected by the fourth sensor 17 dsensing a start position of the reciprocating range.

That is to say, if the sliding flat table 11 advances so that the firstprotrusion 13 a reaches the first sensor 17 a, the spray assembly 80starts printing, while, if the first protrusion 13 a reaches the secondsensor 17 b, the printing work is stopped. In addition, if the firstprotrusion 13 a reaches the third sensor 17 c, the sliding flat plate 11stops advancing. And, if the sliding flat plate 11 moves rearward sothat the second protrusion 13 b reaches the fourth sensor 17 d, the rearmovement of the sliding flat table 11 is stopped.

The guide flat plate 16 is a flat plate to which the gearbox 16 isinstalled, and which is lifted by means of rotation of a rotary shaft60. The guide flat plate 16 has a through hole 19 through which thepinion gear 32 is installed, a guide member 18 for guiding reciprocationof the sliding flat table 11, and sensors 17 a, 17 b, 17 c, 17 d sensingmovement of the sliding flat table 11.

The through hole 19 is formed at a position that ensures close contactbetween the pinion gear 32 and the rack gear 12. The guide member 18 isinstalled to both side ends of the lower surface of the sliding flatplate 11 along its length direction and guides reciprocation of thesliding flat table 11. Such a guide member 18 is widely used inprinters, and not described in detail here. Meanwhile, the sensors 17 a,17 b, 17 c, 17 d are already described above, and not described againhere.

The ascent and descent apparatus 100 is a device for reciprocating thetransferring table 10 in a vertical direction within a predeterminedrange as shown in FIGS. 3 and 4. The ascent and descent apparatus 100includes a rotary shaft 60 vertically installed, and a lifting member 65installed to the rotary shaft 60 to vertically reciprocate thetransferring table 10.

There are installed a predetermined number of rotary shafts 60, whichare rotated by a driving motor 66. The rotary shaft 60 includes a spiralridge 62 formed on its outer circumference, shaft gears 62 a fortransferring a driving force, and a driving force transferring member 67installed for connecting the shaft gears 62 a with each other so as totransfer a driving force.

There are installed a predetermined number of rotary shafts 60 accordingto a size of the transferring table 10. That is to say, though FIG. 4shows four rotary shafts 60 are installed, the number of rotary shafts60 may be suitably increased or decreased according to the size of thetransferring table 10.

The spiral ridge 62 has a shape conforming to a spiral ridge formed onthe inner circumference of the lifting member 65, and it makes thelifting member 65 be lifted when the rotary shaft 60 rotates.

The shaft gear 62 a is installed to each rotary shaft 60 and transfer adriving force of the driving motor 66 to the rotary shaft 60. The shaftgears 62 a are connected with each other by means of the driving forcetransferring member 67. That is to say, the shaft gears 62 a installedto every rotary shaft 60 are interconnected by the driving forcetransferring member 67 and lift the transferring table 10 with rotatingwith the same revolution number.

The driving force of the driving motor 66 is transferred using a firstdriving gear 66 b installed to a driving motor shaft 66 a, a seconddriving gear 66 c installed to the rotary shaft 60, and a belt 66 dconnecting the first and second driving gears 66 b, 66 c. Preferably, atooth row is formed on the belt 66 d so that the first and seconddriving gears 66 b, 66 c are engaged thereto. In addition, RPM of thedriving motor 66 may be suitably controlled using the first and seconddriving gears 66 b, 66 c.

The driving force transferring member 67 transfers a driving forcebetween the shaft gears 62 a. The shaft gears 62 a interconnected by thedriving force transferring member 67 are rotated with the same RPM.Preferably, a tooth row to be engaged with the tooth row of the shaftgear 62 a is formed on one side of the driving force transferring member67. That is to say, the tooth rows are engaged to ensure that a drivingforce is accurately transferred among the shaft gears 62 a.

Preferably, the ascent and descent apparatus 100 is provided with atension pulley 68 that gives a predetermined tension to the drivingforce transferring member 67. The tension pulley 68 is installed betweenthe rotary shafts 60 to curve a path of the driving force transferringmember 67. Thus, the driving force transferring member 67 is closelycontacted with the shaft gears 62 a to transfer a driving force exactly.

Meanwhile, though FIGS. 1, 3 and 4 show that a driving force istransferred using the driving force transferring member 67 and the shaftgears 62 a on which tooth rows are formed, the driving force may betransferred in various ways, not limited to the above case. For example,a driving force may be transferred using sprockets and chain installedto the rotary shafts 60.

Bearing members 63 are installed to upper and lower ends of the rotaryshaft 60 to support rotation of the rotary shaft 60. The bearing member63 has a common configuration supporting shaft behavior, and notdescribed in detail here.

The lifting member 65 is installed to the rotary shaft 60 to support thetransferring plate 10, and has a spiral ridge on its innercircumference, which is engaged with the spiral ridge of the rotaryshaft 60. That is to say, the lifting member 65 lifts the transferringplate 10 with vertically reciprocating as the rotary shaft 60 rotates.

Preferably, the ascent and descent apparatus 100 includes a heightsensor 17 e for sensing a distance between the subject to be coated andthe spray assembly 80, and a controller (not shown) for comparing thedistance with an optimal coating distance required for printing and thenselectively controlling the driving motor 33.

The height sensor 17 e measures the distance between the subject to becoated and the spray assembly 80 and then sends its signal to thecontroller. The controller compares the distance between the subject tobe coated and the spray assembly 80 with an optimal coating distancerequired for printing, and then selectively operates the driving motor33.

As mentioned above, the ascent and descent apparatus 100 for a liquidmaterial spray printer according to a preferred embodiment of thepresent invention may obtain an optimal coating distance suitable forprinting by lifting the transferring table 10 according to size or shapeof the subject. Thus, the liquid material spray printer 200 may beapplied to subjects with various sizes and shapes.

The gearbox 30 is a unit for transferring a driving force from thedriving motor 33 to the rack gear 12, as shown in FIGS. 3 and 5. Thegearbox 30 includes a gear assembly 35 for regulating RPM, and a piniongear 32 for transferring the driving force from the gear assembly 35 tothe rack gear 12.

Preferably, the gear assembly 35 includes an encoder 36 and an encodersensor 37 so as to control movement of the transferring table 10. Thatis to say, the rotation of the encoder 36 may be controlled using theencoder sensor 37 and the controller (not shown) so as to controlmovement of the transferring table 10.

In addition, the gear assembly 35 may further include a tension gear 39giving a predetermined tension to a belt 38. The tension gear 39 makesthe belt 38 move in a curved path, thereby giving a tension to the belt38. The position of the tension gear 39 is controlled using apositioning unit (not shown). That is to say, the positioning unit isused for controlling a magnitude of the tension.

The pinion gear 32 having a common configuration is installed throughthe through hole 19 and transfers a driving force from the gear assembly35 to the rack gear 12.

The gearbox 30 is installed below the guide flat plate 16 by use of thegearbox fixing device 40 as shown in FIGS. 3, 5 and 6.

The gearbox fixing device 40 includes a sliding member 42 for slidablycoupling the gearbox 30 to the guide flat plate 16, and an elasticmember 46 for biasing the pinion gear 32 to be closely contacted withthe rack gear 12.

The sliding member 42 includes an upper slider 43 and a lower slider 44that are combined to be slidable with each other in a length direction.The sliding member 42 is installed between the upper surface of thegearbox 30 and the guide flat plate 16 so that the gearbox 30 may slidewithin a predetermined range in a direction perpendicular to thereciprocating direction of the transferring table 10. That is to say,one of the upper and lower sliders 43, 44 is coupled to the guide flatplate 16, and the other of the upper and lower sliders 43, 44 is coupledto the upper surface of the gearbox 30.

The upper slider 43 has first bending portions 43 a formed in both sideends thereof along its length, a roller member 43 b installed at regularintervals to the first bending portions 43 a, and a coupling hole 43 cfor coupling with the guide flat plate 16, as shown in FIG. 6.

The lower slider 44 includes second bending portions 45 a formed in alength direction thereof to support a shaft 43 d of the roller member 43b, a coupling hole 45 b for coupling with the gearbox 30, andanti-separation projections 45 c formed at both ends thereof to preventthe upper slider 43 from being separated therefrom. The lower slider 44has a width that ensures the upper slider 43 to be installed between thesecond bending portions 45 a.

In the slider member 42 configured as above, the upper slider 43 isinstalled to the lower slider 44, and then the upper slider 43 slideswith respect to the lower slider 44 by means of rotation of the rollermember 43 b. That is to say, as shown in FIG. 5, the upper slider 43 mayslide with respect to the lower slider 44 within a predetermined range,namely between the anti-separation projections 45 c, so the gearbox 30may slide within a predetermined range with respect to the reciprocatingdirection of the transferring table 10.

The elastic member 46 includes an elastic spring 47, and a fixing flatplate 48 for fixing the elastic spring 47 to the guide flat plate 16 asshown in FIG. 5. The elastic member 46 biases the pinion gear 32 to beclosely contacted with the rack gear 12.

The elastic spring 47 has one end connected to the gearbox 30 and theother end connected to the fixing flat plate 48. The number of elasticsprings 47 may be selected in consideration of weight of the gearbox 30and required biasing force.

The fixing flat plate 48 is installed to the lower surface of the guideflat plate 16 and fixes the other end of the elastic spring 47. Thefixing flat plate 48 has a coupling hole 49 in which a coupling memberfor coupling with the guide flat plate 16 is installed.

As mentioned above, the gearbox 30 may slide within a predeterminedrange by means of the sliding member 42 and at the same time the piniongear 32 may be biased by the elastic member 46 to closely contact withthe rack gear 12, thereby preventing the gear from running idle. Thus,it allows accurate and precise printing.

The spray assembly 80 contains liquid material and sprays the liquidmaterial with reciprocating in a direction perpendicular to the movingdirection of the transferring table 10. The spray assembly 80 iscommonly used in printers, and not described in detail here.

Now, the operation procedure of the ascent and descent apparatus 100 fora liquid material spray printer according to a preferred embodiment ofthe present invention is described in detail. The ascent and descentapparatus 100 is installed to a liquid material spray printer 200 andworks together with it, so the operation of the liquid material sprayprinter 200 is described together.

First, a subject (not shown) to be coated is mounted on the uppersurface of the sliding flat table 11. At this time, the subject ispreferably mounted to a position corresponding to the first protrusion13 a. In this case, the first sensor 17 a detects the position of thesubject and controls operation of the spray assembly 80. That is to say,if the sliding flat table 11 advances to make the first protrusion 13 areach the first sensor 17 a, the spray assembly 80 starts printing.

Subsequently, a driving force is transferred to the rack gear 12 so thatthe sliding flat table 11 moves below the spray assembly 80. That is tosay, the sliding flat table 11 advances so that the first protrusion 13a reaches the first sensor 17 a.

After the subject is moved below the spray assembly 80, a controller(not shown) and a height sensor 17 e sense an actual distance betweenthe spray assembly 80 and the upper surface of the subject and thencompare it with an optimal coating distance. After the actual distanceis compared with the optimal coating distance, the ascent and descentapparatus 100 lifts the transferring plate 10 as much as the difference.

That is to say, the driving motor 66 is selectively operated accordingto a signal from the controller to rotate the first and second drivinggears 66 b, 66 c. If the second driving gear 66 c is rotated, the rotaryshaft 60 and the shaft gear 62 a to which the second driving gear 66 cis installed are rotated, and all rotary shafts 60 rotate at the samerevolution number by means of the driving force transferring member 67.As mentioned above, the ascent and descent apparatus 100 rotates aplurality of rotary shafts 60 together at the same speed by means of onedriving motor 66 so that the transferring table 10 may be lifted inparallel.

After the transferring plate 10 is lifted to the optimal coatingdistance, the spray assembly 80 starts printing, and at this same timethe transferring table 10 is moved at a predetermined speed. At thistime, since the gearbox 30 is installed to be slidable in a directionperpendicular to the movement direction of the transferring table 10 andthe elastic member 46 biases the gearbox 30 toward the rack gear 12, thepinion gear 32 is closely contacted with the rack gear 12. That is tosay, the driving force is accurately transferred to move thetransferring table 10 at an accurate speed, thereby ensuring exact andprecise printing.

If the sliding flat table 11 advances and the first protrusion 13 areaches the second sensor 17 b, coating of the liquid material isstopped. In addition, if the first protrusion 13 a reaches the thirdsensor 17 c, the sliding flat table 11 stops advancing.

Subsequently, the driving motor (not shown) transfers a driving forcereversely to move the sliding flat table 11 rearward to a printing startposition.

The present invention has been described in detail. However, it shouldbe understood that the detailed description and specific examples, whileindicating preferred embodiments of the invention, are given by way ofillustration only, since various changes and modifications within thespirit and scope of the invention will become apparent to those skilledin the art from this detailed description.

INDUSTRIAL APPLICABILITY

As described above, the ascent and descent apparatus for a liquidmaterial spray printer according to the present invention may control adistance between a subject to be coated and the spray assembly to anoptimal coating distance required for printing, so it may be applied tosubjects with various sizes and shapes.

1. An ascent and descent apparatus for a liquid material spray printer,comprising: a predetermined number of rotary shafts installed in avertical direction and having spiral ridges on outer circumferencesthereof, the rotary shafts being selectively rotated by a driving motor;and a lifting member installed to the rotary shafts to support atransferring table to which a subject to be coated is mounted, thelifting member having a spiral ridge with a shape conforming to thespiral ridges of the rotary shafts so that the transferring table islifted when the rotary shafts are rotated.
 2. The ascent and descentapparatus for a liquid material spray printer according to claim 1,wherein the rotary shafts include: a shaft gear installed to each of therotary shafts; and a driving force transferring member installed forconnecting the shaft gears with each other so as to transfer a drivingforce, whereby at least two driving rotary shaft are selectively rotatedusing one driving motor at the same time.
 3. The ascent and descentapparatus for a liquid material spray printer according to claim 2,further comprising: a tension pulley installed between the rotary shaftsto make the driving force transferring member be curved so that apredetermined tension is provided to the driving force transferringmember.
 4. The ascent and descent apparatus for a liquid material sprayprinter according to claim 3, further comprising: a sensor for sensing adistance between the subject installed to the transferring table and aspray assembly for spraying liquid material; and a controller forcomparing the distance with an optimal coating distance required forprinting and then selectively operating the driving motor.